Error Concealment in the Network Abstraction Layer for the Scalability Extension of H.264/AVC

This paper presents an error concealment method applied to the Network Abstraction Layer (NAL) for the scalability extension of H.264/AVC. The method detects loss of NAL units for each group of picture (GOP) and arranges a valid set of NAL units from the available NAL units. In case that there is more than one possibility to arrange a valid set of NAL units, this method uses the information about motion vectors of the preceding pictures to decide if the erroneous GOP will be shown with higher frame rate or higher spatial resolution. This method works without parsing of the NAL unit payload or using of estimation and interpolation to create the lost pictures. Therefore it requires very low computing time and power. Our error concealment method works under the condition that the NAL units of the key pictures, which is the prediction reference picture for other pictures in a GOP, are not lost. The proposed method is the first method suitable for real-time video streaming providing drift-free error concealment at low computational cost.